Within the framework of said invention, shaft-type workpieces are to be understood as, for example, gear shafts, rotors for hydraulic pumps or flow meters, rotors for vane pumps and rotors for, for example, compressors for compactors, blowers, vacuum pumps or similar applications. The invention described below, however, is also to be used in terms of a broader interpretation of the designation shaft-type workpieces on other shaft parts such as camshafts, crankshafts, etc. In the case of known methods for the complete grinding of shaft-type workpieces with cylindrical and profiled portions, as is the case, for example, with gear shafts, the necessary incisions, planar sides and diameters are generally ground in separate operating sequences and often also on one machine. In contrast, the profile portions or toothings which are also to be ground on the shaft-type workpieces are ground on separate machines. The use of several machines which are frequently arranged one behind another in the production process requires high investment in tooling machines and an additional requirement for space in the production halls. This also applies to rotor parts which comprise cylindrical and profile portions and are ground for the various applications in a similar manner.
Already disclosed, however, is grinding shaft-type workpieces with cylindrical and profile portions on one machine. The grinding of the cylindrical portions, in this case, also includes, as a rule, the grinding of planar shoulder faces which are present, for example, between adjacent cylindrical outer faces with various diameters. DE 199 21 785 B4 discloses a method for grinding convex running surfaces and outer diameters on shafts with at least one disk-shaped shaft portion and a corresponding grinding machine for implementing the method. The shaft part to be ground is to be ground in terms of complete processing both with reference to the cylindrical portion or the cylindrical portions and to the profile portions. The profile portions are described in the case of said method according to the exemplary embodiment described there as a disk-shaped shaft portion with a convexly curved surface. Such convexly curved surfaces provide profile portions. The disclosed method then is designed to grind all the grinding operations, i.e. one grinding operation to grind the convex end-face running surfaces on the disk-shaped shaft portion and a second grinding operation to grind the respective desired outer diameter or cylindrical portions of the shaft part, in one clamping position. This means that the workpiece remains clamped at least between tips between a workpiece headstock and a tailstock during the entire grinding process. Said clamping position is therefore not released during the entire processing operation.
WO 2012/100 307 A8 describes such a method for the complete grinding of shaft-type workpieces with cylindrical and profiled portions, the profiled portions being helically realized profiles for rotors of, for example, compressors. In the case of said method, the workpiece also remains fixedly clamped during the complete processing operation such that the clamping position is not released. Irrespective of how many grinding operations are carried out in terms of pre-grinding, finish-grinding, grinding a steady rest seat, grinding the cylindrical portions etc., the clamping position of the workpiece is assumed at the start of the grinding operation, and the workpiece remains clamped in said clamping position for the entire duration of the grinding operation.
This also corresponds to the technical expertise known in general today, according to which the workpieces are ground in one single clamping position on one machine to achieve tight tolerances and improved dimensional characteristics. The known expertise currently assumes that at each re-clamping, there are losses in production quality on account of re-clamping errors that may possibly occur.
DE 10 2010 005 630 A1 describes the fundamental technical design of a machine with which shaft-type workpieces can be processed according to previously acknowledged WO 2012/100 307 A8. In the case of said known grinding center, described above all certainly is that in addition it is possible for a hopper magazine to be arranged with cooling jets or cooling jet sets necessary for the changing of respective grinding disks, during the complete grinding operation carried out by means of said grinding center the workpiece also remains completely clamped.